Checksum (CRC16)
Calculation
Example
The checksum (CRC16) is used to detect transmission errors.
If the evaluation reveals an error, the relevant device will not respond.
CRC = 0xFFF
CRC = CRC XOR ByteOfMessage
For (1 to 8)
CRC = SHR (CRC)
if (flag to the right = 1)
thenelse
CRC = CRC XOR 0xA001
while (not all ByteOfMessage edited)
The low byte of the checksum will be transmitted first.
Data query:
Reading 2 words from address 6 (CRC16 = 0x24A0)
0B | 03 | 00 | 06 | 00 | 02 | A0 | 24 |
CRC16
Reply:
(CRC16 = 0x6105)
0B | 03 | 04 | 00 |
| 00 | 42 |
| C8 | 61 |
| 05 |
|
|
|
| Word 1 |
| Word 2 |
| CRC16 | |||
The following functions for the device will be available:
Function number | Function |
0x03 / 0x04 | Reading n words (n 12) |
0x06 | Writing 1 word |
0x10 | Writing n words (n 2) |
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Siemens Building Technologies | CC1A7865.1en |
HVAC Products | 31.10.2002 |
